The invention relates generally to medical devices and, more particularly, to an improved ultrasound probe and a method of using the improved ultrasound probe for treating conditions such as stenotic or occlusive vascular disorders.
At present, stenotic or occluded arteries are commonly treated by using one or several methods, which include, balloon or laser angioplasty, atherectomy and bypass surgery. While these types of treatments have had some success, they each have undesirable side effects. For example, following a balloon angioplasty procedure, the stenosis often rebounds to again obstruct the vessel; laser angioplasty and atherectomy procedures carry the risk of damaging the arterial structure; and bypass surgery is traumatic and requires a prolonged recovery period.
In recent years, a number of devices that use ultrasonic energy to ablate obstructive material from blood vessels have been described in U.S. patents, such as Pat. Nos. 4,870,953 (Don Michael), 4,920,954 (Alliger et al.), and 5,269,287 (Weng et al.), the contents of which are incorporated herein by reference. In general, ultrasound transmitting devices have been reasonably successful when used to ablate obstructions located in peripheral blood vessels, such as the femoral artery. However, conventional ultrasound devices have been shown not to be fully satisfactory. For example, in applications within smaller blood vessels, such as the distal sections of coronary arteries, successful applications have been harder to achieve in practice due in part to the more tortuous paths and smaller vessel diameters involved.
While a number of devices that use ultrasonic energy to ablate obstructive material from blood vessels have been described in recent years, very little has been written about methods of using such devices. One method of ablating material from blood vessels by using heat is disclosed in U.S. Pat. No. 4,773,413 (Hussein et al.), which is hereby incorporated by reference. A second U.S. patent, Pat. No. 5,324,255 (Passafaro et al.), describes a method of using ultrasound to treat vasospasm, the content of which is incorporated herein by reference. However, little has been written on a method of using ultrasound devices, apparently due to a general lack of success in providing a safe, effective ultrasonic device capable of ablating clots.
Accordingly, it is desirable to provide an improved device and method for the treatment of stenotic or occluded arteries and the like which overcomes shortcomings of the prior art.